An investigation of the influence of the amount and degree of unsaturation of dietary fat on the uptake, storage, and binding of 7,12-dimethylbenz(alpha)anthracene (DMBA) in mammary gland parenchymal cells and mammary fat pad cells, and how the presence of absence of antioxidants affects these parameters and tumor incidence is proposed. Preliminary studies indicate that polyunsaturated fat in the diet is more antagonistic to the inhibitory effect of antioxidants on tumorigenesis than either a saturated fat diet or low fat diet, possibly due to the high peroxidative capabilities of unsaturated fats. The content of antioxidant in these two mammary cell types will be determined at various times before and after carcinogen administration, and related to the actual uptake and binding of carcinogen by the mammary parenchymal and fat cells. Binding of labelled DMBA to the mammary parenchymal cell, DNA, RNA, and cellular proteins at various time intervals after DMBA administration will be determined in animals in the various dietary fat groups and with or without antioxidant. Levels of peroxidase, peroxides, catalase, and lipid peroxidation as well as total DNA, RNA, and protein of the isolated mammary parenchymal cells and fat pad cells will be determined in animals on the various diets. This information will also be correlated with the uptake and binding of DMBA by the cells as well as the antioxidant content of the cells at various time intervals after DMBA administration and in animals on the different fat diets. The most critical time for the presence of antioxidant in mammary cells, whether for a short time before, during, or after treatment with DMBA or if a long-term maintenance is required to decrease tumor incidence, will be investigated. These studies will be done using both in vivo and in vitro exposure to antioxidants. The studies described in this project are thus designed to probe the interrelationships of antioxidants and dietary fat level and type on the uptake, storage and binding of DMBA at the level of the mammary gland parenchymal cell and fat pad cell.